Experimental and theoretical study of the equation of state of liquid ethylene

Abstract

A gas-expansion method has been used to measure the density of liquid ethylene at 19 temperatures between 110 and 280 K and at pressures up to 1300 bar. The results have been fitted to an equation of state that has been used to calculate the following properties of the compressed liquid: density, isothermal compressibility, thermal expansivity, thermal pressure coefficient, configurational internal energy, and entropy relative to the entropy of the ideal gas at the same density and temperature. The following properties of the saturated liquid have been calculated: enthalpy of vaporization, configurational internal energy, isothermal compressibility, thermal expansivity, and thermal pressure coefficient. The densities and mechanical coefficients were also estimated for the liquid along the melting line. The density, internal energy, and entropy results have been interpreted in the light of a perturbation theory using several intermolecular potential models for ethylene.